d. Edge Effects During Nourishment. Animals near the nourishment activity 
but not subject to actual burial were also subjected to stress. Three special 
transects were established in an attempt to evaluate this stress. On 19 March 
one transect was established near the nourishment activity but outside the area 
actually receiving materials that day. This special study transect yielded two 
small —. talpoitda from the swash zone but no other organisms. This yield was 
low in relation to the following average densities per transect obtained from 
the unnourished part of the beach that same day: 16 EF. talpotda, 1 H. 
canadensts, 2 D. vartabtlts, and 1 D. parvula. 
Two more special study transects were established on 5 May 1978. By that 
time nourishment had proceeded to near the park's western boundary. Thus, no 
"prenourishment" section remained on the Fort Macon beach. The results of 
these special transects were compared to the data obtained the same day from 
the unnourished comparison beach at Emerald Isle. The special transects were 
worked, but no organisms were recovered. An attempt was then made to determine 
if any organisms were present by carrying out an intensive, nonquantitative 
digging and sieving effort. No #. talpoitda were recovered; however, a few 
Donax spp., some amphipods (H. canadensts and T. megalopthalma), and a small 
number of S. squamata were found. The Emerald Isle comparison beach that day 
yielded an average of 14 £. talpotda, 38 D. parvula, 45 D. vartabilis, 3 H. 
ecanadensts, 4 Amphtporeta virginiana, and 1 T. megalopthalma per transect. 
This special study is useful because it serves to further implicate the 
increased turbidity associated with nourishment activities as a prime environ- 
mental stress factor during nourishment. This part of the study proves that 
impacts to the adjacent beach and nearshore waters can be profound, and it 
demonstrates that organisms in the nourishment area may not always simply move 
to adjacent unnourished areas during nourishment, as was observed by Dolan 
(1974) and Hayden and Dolan (1974). Organisms are either killed or they are 
driven from the nourishment area and its immediate vicinity. 
5. Prenourishment and Postnourishment Population Dynamics. 
a. Emerita talpotda. This common mole crab is the dominant organism on 
high-energy psammolittoral beaches in North Carolina (Matta, 1977; Leber, 1977). 
During this study, £. talpotda densities reached a prenourishment maximum 
density of 1,416 individuals per square meter in late summer 1977. At this 
time, Z. talpotda completely dominated the swash and saturated zones, and were 
present in every other tidal zone. The autumn maximum density of 976 indi- 
viduals per square meter which occurred at Fort Macon, closely matched the 
autumn maximum recorded at the comparison beach (1,096 individuals per square 
meter). Both populations declined rapidly as winter approached (Fig. 20). 
Nourishment started in December, causing the mole crab population at Fort 
Macon to fall to zero. Meanwhile, the mole crab population at Emerald Isle 
continued its steady decline. From the onset of nourishment to April, no 
crabs were found on the nourished area of the beach (Fig. 18). All crabs 
reported from the Fort Macon beach during this time were found on the unnour- 
ished part of the beach. 
Both beaches showed a rapid recovery in mole crab density with the onset 
of spring (Fig. 20); however, the population at Fort Macon lagged behind that 
of Emerald Isle by 1 month in April when recolonization began, and by 2 weeks 
38 
